It's the purity test all over again; only this time, the stakes are high and the weird are turning seriously pro.

Not that the tea partiers are weird, not most of them, anyway. But some are at risk of flying off into the blood-red zone of wing-nuttery. One of the sessions at the recent Conservative Political Action Conference (CPAC) questioned whether Abraham Lincoln was "friend or foe."

Lincoln foes can't be said to define CPAC conferees — and certainly not the GOP — but the growing libertarian strain within the party (See Ron Paul's straw poll victory) combined with an anti-RINO (Republicans In Name Only) attitude is making life increasingly difficult for moderates such as Brown.

Brown came under fire from social conservatives barely a week into his new job, even though his pro-choice position was well-known, at least to readers of this column.

Now he's caught the attention of fiscal conservatives and tea partiers who, though they favored Brown for his anti-health reform and anti-stimulus positions, now call him a traitor for supporting a cloture motion on the Democrats' $15 billion jobs bill.

Thousands posted angry comments on Brown's Facebook page, including the ever-popular "YOU LIED!" Brown said that though the bill was imperfect, it would put Americans back to work. He also said he hoped his vote would be a "strong step toward restoring bipartisanship in Washington."

Guess again, Scottie. "True conservatives" want to beam you up.

Zero cooperation with Democrats apparently is the preferred MO for the noisiest sector of the GOP. Although some tea partiers are independents and even Democrats, the majority lean toward the GOP and they are, above all, fiscally conservative. And though there's no centralized organization and no leader, some segments find nullification and, apparently, secession reasonable alternatives to failed politics and a gorging government.

These true conservatives and RINO-hunters are, to put it mildly, a problem for any candidate or incumbent who tries to speak bipartisan, which translated means "treason."

The hunt for RINOs isn't new. Ask John McCain. Or John Avlon, author of the new book "Wingnuts," who traces the mainstreaming of the hyperpartisan hunt for heretics to the George W. Bush administration.

He cites, for example, Monica Goodling, the Justice Department White House liaison who imposed social conservative litmus tests on prospective employees. The hunts escalated during the 2008 presidential campaign when certain individuals who need not be named were "outed" as apostates for not walking lockstep with the McCain-Palin ticket.

Writes Avlon: "Hunting for heretics pretends to be a principled fight for ideological purity, but behind that mask is an uglier impulse, an attempt to intimidate and insist on conformity ... a reminder of what the Czech dissident-turned-president Vaclav Havel once wrote:

'Ideology offers human beings the illusion of dignity and morals while making it easier to part with them.'"

Who emerges pure enough from this fray of fraying parts will be interesting to watch, but things could get messy as the tea party movement gains momentum and old alliances show signs of weakening. The other day,

The Weekly Standard's Bill Kristol made a remark on "Fox News Sunday" that may predict fissures to come:

"The tea parties are the best thing that has happened to the Republican Party in recent times."

Really?

Less than 10 years ago, Kristol's father Irving Kristol, the founder of the neoconservative movement, concluded that neocons couldn't align themselves with libertarians because they have no values. Neocons' natural allies, said the elder Kristol, were religious conservatives. From that alliance came what Bill Kristol's magazine designated as "Big Government Conservatism" and Bush 43-era policies unbeloved by most Americans these days.

And now? Tea partiers don't much favor endless wars or care about social issues dear to evangelicals. Another CPAC panel that drew a packed crowd despite scheduling opposite Newt Gingrich was titled: "You've Been Lied To: Why Real Conservatives Are Against the War on Terror."

Are neocons abandoning the old party base and following the new wave of power created by the tea party movement? As one tea drinker put it to me: "How the neocons square limited government at home with big government nation- building abroad will be interesting to watch."